The best way is to provide high quality, value-added content without spamming keyword rich anchors back to your blog. Guest posting, when done properly, can still be an effective link building strategy if it doesn't minimize the content.
For example, find a highly related niche website and write up an insightful, lengthy article (none of that 300 word crap). In that article, touch briefly on a related topic that you've expanded upon in detail on your own website - like an aside note where a reader can visit to gain deep understanding on a supplemental topic. If both articles (the guest post and your own article) are unique and high quality, the contextual link should be a positive addition to your link portfolio.
You want it to be seen as natural and appropriate - not spammy and an obvious tactic at only receiving a link. Keep the readers' best interest in mind and you should be ok, as long as the quality of the website you're guest blogging on also executes legitimate link building strategies.
What topics are you intending to write about?